Dang. You stole my idea.... Looks good and makes sense. The top two switches don't make sense if you don't have those features.

Haha, sorry. Was a bit worried about tearing up the 400 switch box, but yeah, just popped the extra buttons off. I can't confirm the CC works because I've not done the Calibration yet but 4lo was working no problem.

Did the switches snap/break? Or are they just rough and unfinished on the bottom side? The picture looks like they broke off.

That white stuff is just some type of lube to keep the buttons from squeaking as far as I can tell. The toggle switches are just held on by the sides and pop off easily (you can see the little holes where mating part is connected). The blank button and on/off push button were really hard to get off, I used that tiny screw driver you see in the picture, stuck it through the bottom side of the button and hit it very hard against my work bench and it popped it off, its on there pretty good and will take some force, just be careful and make sure you have a concept of how its on there before trying my ape method.

Probably about an hour, but I had taken apart a lot of those parts before so I just dove right in. The lower kick panel below the box is a bit tricky and the clips are pretty tight. I didn't remove the whole thing - just enough to get the interior of the glove box out of the way so I could stick my hand in there to unbolt the old computer. Budget a couple hours if you haven't been in there already.